I have a 1988 Ford ranger xlt with a extended cab and with 2 fuel tanks and also has the 2.9 fuel injected engine. The fuel pumps dont receive power unless everything is bypassed. I have check all the fuses and relays and cant find a short anywhere in the wire from when I traced the wiring from the battery to the fuel pump. And the roll over switch has been removed from the circuit. Does anyone know if I am missing anything?

 

Welcome to the forum

1988 Ranger with 2.9l will have a fuel pump in each gas tank and then one high pressure pump on the frame rail under drivers seat area

The 12volt power comes from a fuse or fusible link in the engine bay, it has 12volt full time, not key on/off power
The fuel pump power is controlled by the engine computer(PCM) via a Relay also in the engine bay, has a green base

Power path for single tank set up
12v------Fuel pump relay--------inertia switch------------------high pressure pump------------------in tank pump-----ground

In a Dual tank setup with electric switch on the dash
12v------Fuel pump relay--------inertia switch---------><---------high pressure pump----ground

><---------Dash Tank switch-------------------in tank pump---ground

>< indicates a splice at or after the inertia switch(roll over switch) with a wire that runs to the dash switch
Dash switch decides which tanks fuel pump gets the 12volts, but the high pressure pump gets 12volts regardless of the switch setting

Diagram of that type of setup seen here: https://www.ford-trucks.com/forums/a...8&d=1683216609


You have an OBD1 system so will have an OBD1 connector in engine bay, passenger side main wiring harness
Looks like this: https://www.therangerstation.com/tec...v_testing2.gif

In that drawing the Fuel Pump slot is labelled
That is the GROUND for the fuel pump relay
Get a Jumper wire and put it in that slot
Turn on the key
Ground the other end of the jumper wire, battery negative or bare metal
You should hear a "click" when Fuel Pump Relay closes, unground and another "click" when it opens, repeat
If no "clicks" then FP relay is not working
You can ground that slot full time for testing, that is what the computer does once engine is running, FP relay will go off with key off

The FP relay sends 12v to the inertia switch and the Tank selector switch, so that's the start of the 12volts

But there is also the Fuse/fusible link that feeds 12v to the FP relay, so that's the real start of the 12v chain to fuel pumps